Bug 706257: CIDFont glyph ordering issues with pdfi/pdfwrite

This exposed a couple of issues:

Firstly, and most importantly, when pdfwrite uses the callback to retrieve the
glyph index for text in a CIDFont, it uses the descendant font, not the Type 0,
as I originally thought. For embedded CIDFonts, that didn't cause a problem, but
for substituted CIDFonts it meant the glyph decoding callback did not have
access to the decoding table.

Secondly, fixing that exposed some byte ordering issues, where Unicode codes
read from the ToUnicode CMap differed in byte order from codes read from the
decoding table.

1 files changed, 11 insertions, 41 deletions

diff --git a/pdf/pdf_font0.c b/pdf/pdf_font0.c
index 51cf4989a..594a79a40 100644
--- a/pdf/pdf_font0.c
+++ b/pdf/pdf_font0.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2019-2022 Artifex Software, Inc.
+/* Copyright (C) 2019-2023 Artifex Software, Inc.
    All Rights Reserved.
 
    This software is provided AS-IS with no warranty, either express or
@@ -34,35 +34,6 @@
 
 #include "gsutil.h"        /* For gs_next_ids() */
 
-extern const pdfi_cid_decoding_t *pdfi_cid_decoding_list[];
-extern const pdfi_cid_subst_nwp_table_t *pdfi_cid_substnwp_list[];
-
-static void pdfi_font0_cid_subst_tables(const char *reg, const int reglen, const char *ord,
-                const int ordlen, pdfi_cid_decoding_t **decoding, pdfi_cid_subst_nwp_table_t **substnwp)
-{
-    int i;
-    *decoding = NULL;
-    *substnwp = NULL;
-    /* This only makes sense for Adobe orderings */
-    if (reglen == 5 && !memcmp(reg, "Adobe", 5)) {
-        for (i = 0; pdfi_cid_decoding_list[i] != NULL; i++) {
-            if (strlen(pdfi_cid_decoding_list[i]->s_order) == ordlen &&
-                !memcmp(pdfi_cid_decoding_list[i]->s_order, ord, ordlen)) {
-                *decoding = (pdfi_cid_decoding_t *)pdfi_cid_decoding_list[i];
-                break;
-            }
-        }
-        /* For now, also only for Adobe orderings */
-        for (i = 0; pdfi_cid_substnwp_list[i] != NULL; i++) {
-            if (strlen(pdfi_cid_substnwp_list[i]->ordering) == ordlen &&
-                !memcmp(pdfi_cid_substnwp_list[i]->ordering, ord, ordlen)) {
-                *substnwp = (pdfi_cid_subst_nwp_table_t *)pdfi_cid_substnwp_list[i];
-                break;
-            }
-        }
-    }
-}
-
 static int
 pdfi_font0_glyph_name(gs_font *pfont, gs_glyph index, gs_const_string *pstr)
 {
@@ -134,17 +105,17 @@ pdfi_font0_map_glyph_to_unicode(gs_font *font, gs_glyph glyph, int ch, ushort *u
                 if (cc > 65535) {
                     code = 4;
                     if (unicode_return != NULL && length >= code) {
-                        unicode_return[0] = (cc & 0xFF000000)>> 24;
-                        unicode_return[1] = (cc & 0x00FF0000) >> 16;
-                        unicode_return[2] = (cc & 0x0000FF00) >> 8;
-                        unicode_return[3] = (cc & 0x000000FF);
+                        unicode_return[3] = (cc & 0xFF000000)>> 24;
+                        unicode_return[2] = (cc & 0x00FF0000) >> 16;
+                        unicode_return[1] = (cc & 0x0000FF00) >> 8;
+                        unicode_return[0] = (cc & 0x000000FF);
                     }
                 }
                 else {
                     code = 2;
                     if (unicode_return != NULL && length >= code) {
-                        unicode_return[0] = (cc & 0x0000FF00) >> 8;
-                        unicode_return[1] = (cc & 0x000000FF);
+                        unicode_return[1] = (cc & 0x0000FF00) >> 8;
+                        unicode_return[0] = (cc & 0x000000FF);
                     }
                 }
             }
@@ -335,11 +306,10 @@ int pdfi_read_type0_font(pdf_context *ctx, pdf_dict *font_dict, pdf_dict *stream
             olen = pcmap->csi_ord.size;
         }
         if (rlen > 0 && olen > 0)
-            pdfi_font0_cid_subst_tables(r, rlen, o, olen, &dec, &substnwp);
-        else {
-            dec = NULL;
-            substnwp = NULL;
-        }
+            pdfi_cidfont_cid_subst_tables(r, rlen, o, olen, &dec, &substnwp);
+
+        ((pdf_cidfont_t *)descpfont)->decoding = dec;
+        ((pdf_cidfont_t *)descpfont)->substnwp = substnwp;
     }
     /* reference is now owned by the descendent font created above */
     pdfi_countdown(decfontdict);